Conventional air-fuel delivery systems can be broadly divided into two types: carburetion and fuel injection. The carburetion system only permits the use of light fuel oil and is becoming increasingly complex in mechanism because of the need to meet the recent emission control requirements with the consequential increase in cost. Fuel injection for Diesel engines employs a fuel pump for compressing air and, at the point of maximum compression, heavy fuel oil is injected into the combustion chamber and ignition takes place as a result of the high temperature which has been created. In electronic fuel injection, the fuel injectors are essentially solenoid actuated on/off poppet valves incorporating pintles designed for metering and atomization of light fuel oil, which requires precision in machining and becomes costly in mass production.